macro_rules! result_match {
{match $e1:expr => $p1:pat_param, $(match $es:expr => $ps:pat_param,)* create $body:expr} => { ... };
{create $body:expr} => { ... };
}macro_rules! result_match {
{match $e1:expr => $p1:pat_param, $(match $es:expr => $ps:pat_param,)* create $body:expr} => { ... };
{create $body:expr} => { ... };
}